Patent GB-709463-A (GB)
Title: Improvements in apparatus for registering the output of a machine
IPC: H03K21/02
Filed: 1952-03-26
Abstract: 709,463. Registering output of machines. AMERICAN MACHINE & FOUNDRY CO. March 26, 1952 [March 26, 1951], No. 7737/52. Class 106 (4). [Also in Group VI] Apparatus for use with a machine producing a material in a continuous stream, includes means for registering the movement of a part of the machine the movement of which is related to the movement of the continuous stream and thereby indicating the amount of material produced, means for generating a fluctuating voltage by the movement of the stream of material, and control means for causing the registering means to be effective only when the presence of the fluctuating voltage indicates that the material is moving. A cigarette-making machine of the type in which cigarettes are produced in the form of a continuous rod R and later cut into separate cigarettes, comprises a counter 36 driven by the machine via a magnetic clutch 40. To ensure that the counter operates only as long as the cigarette rod R is moving towards the cutting off device, electrodes 8 are located adjacent the moving rod so as to form a condenser, the tobacco-filled tube serving as dielectric, the impedance of which varies while the rod is moving. With suitable amplification these variations are utilized to indicate motion of the rod and maintain the magnetic clutch 40 in engagement. A double-triode push-pull oscillator 129 generates a radio-frequency voltage in a Wheatstone bridge circuit which includes in one arm a variable resistor 120, variable capacitor 122 and fixed capacitor 144, and in another arm, D.C. blocking capacitors 114 and 146 and the capacitor formed by the electrodes 8 and cigarette rod R. This arrangement gives rise to an RF signal modulated in response to the fluctuations caused by the moving stream of tobacco dielectric. The output is applied to a circuit 148, 150 tuned to the frequency of the oscillator, and then fed via an R.F. amplifier 163 to a second tuned circuit 168; 170. Rectification by a diode 181 provides a voltage across a resistor 184 varying in correspondence with the fluctuations in dielectric value of the cigarette rod. The D.C. component of this signal is blocked by a condenser 189 and the A.C. voltage is applied to the grid of a triode 203 which is biased to pass relatively low current, insufficient to hold in a relay 204 in its anode circuit unless the fluctuating voltage exists at the grid, the positivegoing excursions of which give greater increase in anode current than the decrease during the negative-going excursions. Adjustment is provided for by a variable resistor 196; there is also a variable resistor 154 in the cathode circuit of the amplifier 163, and this will generally require adjustment in accordance with the quality of the cigarettes being produced. The adjustment of variable resistor 154 might be made automatic. An indicator lamp L which lights when the clutch 40 is operated by the relay assists in making manual adjustments. In a second embodiment, Fig. 3 (not shown), the cutter forms one electrode of the tobaccocondenser arrangement which is connected across the tuned circuit of an oscillator. The additional impedance introduced each time the knife cuts across the cigarette rod causes the oscillator to drop out of oscillation and a voltage pulse is transmitted to an electric decade counter which, in turn, drives a mechanical counter. Specification 707,238, [Group VI], is referred to.